1. Field of the Invention
The present invention relates to a liquid droplet discharge head and a liquid droplet discharge apparatus provided with the same.
2. Description of the Related Art
An ink-jet printer has been hitherto known as one of the liquid droplet discharge apparatus, including an ink-jet head (liquid droplet discharge head) provided with a flow passage unit which has a plurality of pressure chambers formed regularly, a piezoelectric actuator which is joined to the flow passage and which is provided to selectively discharge the ink contained in each of the pressure chambers, and a voltage-applying mechanism which applies the voltage to the piezoelectric actuator. In order to realize the high image quality and the high quality of the recording by increasing the number of nozzles in the ink-jet head as described above, it is required to highly density the pressure chambers. When the pressure chambers are arranged at a high density, the distance between the adjoining pressure chambers is shortened. Therefore, the influence, i.e., the so-called crosstalk is caused, which is exerted on the adjoining pressure chamber when the piezoelectric actuator is driven.
U.S. Pat. Nos. 7,008,048 and 7,290,865 (corresponding to Japanese Patent Application Laid-open No. 2003-311954) suggest structures to suppress the crosstalk. An ink-jet head described in U.S. Pat. Nos. 7,008,048 and 7,290,865 include individual electrodes having main electrode sections 35a which are formed on a piezoelectric sheet 41 separated farthest from the pressure chambers 10 in an actuator unit 21. Grooves 61a, 61b, which are “L-shaped”, are formed on the both sides of the main electrode section 35a corresponding to areas disposed between the main electrode section 35a and the main electrode sections 35a of the adjoining individual electrodes. According to this structure, the grooves 61a, 61b are formed in the areas corresponding to the areas disposed between the adjoining pressure chambers 10 in the actuator unit 21. Therefore, it is possible to suppress the crosstalk in which the deformation of the active layer, which is brought about by the piezoelectric effect, affects the adjoining pressure chamber.
According to the ink-jet head described in U.S. Pat. Nos. 7,008,048 and 7,290,865, the amount of deformation, which is transmitted to the active layer of the adjoining pressure chamber when the active layer corresponding to a certain pressure chamber is deformed, is decreased owing to the formation of the grooves 61a, 61b as compared with a case in which the grooves 61a, 61b are not formed. However, it is requested to realize a higher image quality, and it is also demanded to provide a higher density in relation to the arrangement of the pressure chambers. Therefore, any countermeasure against the crosstalk, which is more excellent than the above, has been requested. In view of the above, the present inventors have invented a structure of an actuator as described later on. However, in order to stabilize the operation of the actuator in such a structure, a problem exists in relation to the wiring.